HEXACTINELLIDA. 15 
With hypodermal pentactins with short, thick, smooth paratangentials, associated with 
conules or bundles of pleuralia ; hypodermal pentactins entirely absent from the areas 
between the conules. 
The new genus resembles ossella in possessing three kinds of discohexasters 
including calycocomes, but differs from it in the character and distribution of the 
hypodermal pentactins. 
In the absence of the hypodermal pentactins from the interconular areas Au/o- 
rossella approaches Aulosaccus, in which these spicules are entirely lacking. In 
Seyphidium longispina Ij. the same spicules are restricted to the upper part of the 
body, and, in that situation, mostly to the conules; but Scyphidium is devoid of 
the calycocomes, and so also is Vitrollula Tj. Possibly when pleuralial bundles 
are strongly developed, the autodermal surface is less in need of support by means 
of a layer of hypodermal pentactins, and these latter become restricted to the conules, 
and their paratangential rays become shortened till they disappear altogether. 
In Aulorossella levis sp.n. only a very few anchor-like pentactins are present in 
the bundles of pleuralia prostalia; but these spicules are very abundant in the 
pleuralial bundles of A. crassa, the pentactins being here wholly covered by the 
dermal membrane. Apropos of the origin of the anchor-like pleuralia and_basalia, 
Schulze observes (8, p. 83): “This leads me to suppose that the anchors are to 
be considered as protruded and enlarged hypodermalia.” At first the three species 
of Awlorossella described below were placed under Aulosaccus. Prof. Ijima, in his 
description of Aulosaccus schulzei \j., the type of the genus Aulosaceus, expressly 
states, however (5, 112), that no pentactins enter into the composition of the hypo- 
dermal skeleton ; and, further, only two kinds of discohexasters occur. 
Apropos of the presence or absence of hypodermal pentactins, it will not, I 
think, be out of place to make here a slight correction concerning the species 
of Aulosaccus Tjima (5, p. 252 and p. 107), in which genus Prof. ljima_ places 
three species, viz., A. schulzei Tjima, A. yimai Schulze, and A. mitsukurii Tima. 
If Schulze (7, pp. 30, 100, and 10, p. 176) is right in retaining Calycosaccus for 
C. yimai Schulze on account of its markedly pinula-like autodermal and autogastral 
hexactins with their long obliquely directed spines, then Aulosaccus contains only 
one species, viz., A. schulzei Tjima; the species mitsukurii belongs, as will be 
shown below, to Seyphidium. 
With regard to Seyphidium mitsukurii Tjima, the British Museum possesses the 
specimen referred to by Prof. Ijima (5, p. 121) as O.C. No. 4399, and stated by 
him to be specifically identical with the type of Seyphidiwm (Aulosaccus) mitsukurii. 
The specimen is badly preserved, and patches of dermal membrane remain only here 
and there; but in these patches, and beneath the autodermalia, there are hypodermal 
pentactins with orthotropal smooth paratangential rays. Prof. [ima himself says 
(5, p. 109): “If A. mitsukurii were only provided with pentactinic hypodermalia 
I should have no hesitation in referring it to Seyphidium.” Among the autodermal 
